ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Effect of Structure of Turbulence on Drop Breakage

W. Podgórska and J. Baldyga

Faculty of Chemical and Process Engineering, Warsaw University of Technology, PL-00 645 Warsaw

E-mail: podgorsw@ichip.pw.edu.pl

Received: 1 April 2002

Abstract: Possibilities of using several known models of microstructure of turbulence to model drop breakup rate are presented. The classical theory of turbulence neglects fine-scale intermittency. Here, intermittency is taken into account and modelled using multifractal formalism when applied to the inertial sub-range of turbulence. Maximum stable drop size, predicted by the classical theory of turbulence that neglects its intermittent character, is unequivocally determined by the mean energy dissipation rate and does not depend on the scale of the system provided that the mean energy dissipation rate is kept the same in each system. The breakage kinetics based on multifractal models of turbulence suggests a slow drift of the quasi-stable drop size to the stable drop size that is determined by the most vigorous turbulent events. Drop size distributions predicted by multifractal models are compared with predictions of the model based on the classical Kolmogorov theory of turbulence and with experimental data. All multifractal models predict the changes of the drop size in time better than the model based on the classical theory and are recommended to model the breakage processes.

Full paper in Portable Document Format: 566a412.pdf

Chemical Papers 56 (6) 412–417 (2002)